Thanks for the replies. My tractor is out at my other property at the moment so I can't get any pics or measurements and as far as I can tell the tires are not filled, though I do plan to get them done. I was just hoping someone could give me a definitive answer as my other place is very hilly and I'd like go get all the stability I can.
Getting the tires filled will definitely help - both with stability & with ground engaging work like the Box Blade & Tiller you list.
I cheated and searched your posts and I saw that this is your first tractor - when dealing with hills, grades, slopes, etc the learning curve is steep (sorry I couldn't resist the pun) but it's also very intolerant of mistakes.
As a general rule of thumb going down slope is better than going up, and going across is always the last choice.
Carry the loader and rear implements as low as reasonably possible to keep your center of gravity low - always not just on slopes.
The operator seat on these tractors sits pretty far up (imagine standing behind the tractor and drawing a line from rear wheel to rear wheel directly thru the seat bottom, then see how far that line is up above the center line of the axle and how far off the ground). Being that far "up" makes every side tilt feel steeper than it really is because the higher you are above the axle, the farther you "shift" or tilt when the axle isn't level.
Our CK35 and 8N Ford have the same basic wheel base and track width and the same size rear tire but the operators seat on the 8N sits much farther down between the wheels closer to the axle so riding both tractors across the same slope feels noticeably different.
Although I would suggest & urge you to do this all the time, I know how complacency & human nature are and eventually we get out of good habits thru comfort, BUT - till you get to know the tractor and the ground you're working keep your ROPS up and your seat belt on!!
Other than that, just stay safe and enjoy.
